Field of the Invention
This invention relates in general to electrostatic discharge protection circuitry for integrated circuits.
Description of the Related Art
Integrated circuits are sensitive to Electrostatic Discharge (ESD) events. An ESD event may occur from the unwanted quick discharge of a charged object or person and produce a high charge current for a short period of time through structures of the integrated circuit. For example, a person carrying a relatively small amount of charge may inadvertently touch the electrical terminals of the integrated circuit where charge from the person is transferred to the integrated circuit. In some instances, the amount of current from an ESD event is high enough to damage the circuitry of the integrated circuit.
To protect against ESD events, an integrated circuit may include ESD circuitry that allows for the relatively safe discharge of current from an ESD event to system ground. For examples, an integrated circuit may include trigger circuits that detect an ESD event at a terminal and camp circuits that, when activated by the trigger circuits, become conductive to provide a path for the current to flow from the terminal to ground.
The use of the same reference symbols in different drawings indicates identical items unless otherwise noted. The Figures are not necessarily drawn to scale.